AtObgC-AtRSH1 interaction may play a vital role in stress response signal transduction in Arabidopsis

详细信息    查看全文

• 作者：Ji Chen ; Woo Young Bang ; Yuno Lee ; Songmi Kim ; Keun Woo Lee ; Se Won Kim ; Young Sim Son ; Dae Won Kim ; Salina Akhter ; Jeong Dong Bahk
• 关键词：Chloroplast ; AtObgC ; AtRSH1 ; ppGpp ; Stress response ; Arabidopsis thaliana
• 刊名：Plant Physiology and Biochemistry
• 出版年：January, 2014
• 年：2014
• 卷：74
• 期：Complete
• 页码：176-184
• 全文大小：1892 K

文摘

The interaction of Obg (Spo0B-associated GTP-binding protein) GTPase and SpoT, which is a bifunctional ppGpp (guanosine 3鈥?5鈥?bispyrophosphate) hydrolase/synthetase, is vital for the modulation of intracellular ppGpp levels during bacterial responses to environmental cues. It has been recently reported that the ppGpp level is also inducible by various stresses in the chloroplasts of plant cells. However, the function of the Obg-SpoT interaction in plants remains elusive. The results from the present and previous studies suggest that AtRSH1 is a putative bacterial SpoT homolog in Arabidopsis and that聽its聽transcription levels are responsive to wounding and salt stresses. In this study, we used a yeast聽two-hybrid analysis to map the regions required for the AtObgC-AtRSH1 interaction. Moreover, protein-protein docking simulations revealed reasonable geometric and electrostatic complementarity in the binding surfaces of the two proteins. The data support our experimental results, which suggest that the conserved domains in AtObgC and the N terminus of AtRSH1 containing the TGS domain contribute to their interaction. In addition, quantitative real-time PCR (qRT-PCR) analyses showed that the expression of AtObgC and AtRSH1 exhibit a similar inhibition pattern under wounding and salt-stress conditions, but the inhibition pattern was not greatly influenced by the presence or absence of light. Based on in聽vivo analyses, we further confirmed that the AtRSH1 and AtObgC proteins similarly localize in chloroplasts. Based on these results, we propose that the AtObgC-AtRSH1 interaction plays a vital role in ppGpp-mediated stress responses in chloroplasts.